Connect to remote docker host - docker

Question

I have following scenario.
Two Machine ( Physical Machine)
One is Windows 10 With Docker On Windows Installer and same way ubuntu 18.04 with docker-ce installed.
I can run command on individual and that is fine.
I want to connect Ubuntu Docker Host from Docker on Windows machine. So Docker CLI on Windows Point to deamon at Ubuntu Host.

Answer 1

You will need to enable docker remote API on Ubuntu Docker Host by adding below settings in daemon.json or your startup script
[root#localhost ~]# cat /etc/docker/daemon.json
{
"hosts": [ "unix:///var/run/docker.sock", "tcp://0.0.0.0:2376" ]
}
Once you restart docker you can connect to docker host locally by socket file and remotely by listening port (2376).
Verify the listening port of docker on Ubuntu
[root#localhost ~]# netstat -ntlp | grep 2376
tcp6 0 0 :::2376 :::* LISTEN 1169/dockerd
Now you can connect to this docker from Windows machine by setting the DOCKER_HOST env variable in Windows like this
PS C:\Users\YellowDog> set DOCKER_HOST=tcp://<Ubuntu-Docker_Host-IP>:2376
PS C:\Users\YellowDog> docker ps
It will list docker containers running on Ubuntu Docker Host

Answer 2

You can also do this through additional options to the service:
Find original ExecStart line docker.service:
systemctl status docker | grep load | grep -oP "\/.+service"
# --> /lib/systemd/system/docker.service
cat /lib/systemd/system/docker.service | grep ExecStart
ExecStart=/usr/bin/dockerd -H fd:// $DOCKER_OPTS
Create a new file to store the daemon options:
sudo mkdir /etc/systemd/system/docker.service.d/
Add next lines with -H unix:// -H tcp://0.0.0.0:2375 options to /etc/systemd/system/docker.service.d/options.conf:
cat <<EOF > /etc/systemd/system/docker.service.d/options.conf
[Service]
ExecStart=
ExecStart=/usr/bin/dockerd -H fd:// \$DOCKER_OPTS -H unix:// -H tcp://0.0.0.0:2375
EOF
Here you need to pay attention to the escaping $DOCKER_OPTS variable if it exists.
Or using your favorite editor, for example vim.
Now, reload the systemd daemon and restart the docker service:
# Reload the systemd daemon.
sudo systemctl daemon-reload
# Restart Docker.
sudo systemctl restart docker
Configuring your dev box to connect to the remote Docker daemon:
If you want to set DOCKER_HOST by default so it always connects remotely you can export it in your ~/.bashrc file.
Here’s an example of that as a 1 liner:
echo "export DOCKER_HOST=tcp://X.X.X.X:2375" >> ~/.bashrc && source ~/.bashrc
Or use it all at once:
DOCKER_HOST=tcp://X.X.X.X:2375 docker ps